In the production of rod-shaped articles such as cigarettes, the articles come from a rod maker either as individual articles or as a continuous rod which is cut or otherwise separated into individual articles of a desired length. Such rod-shaped articles are aligned initially in a serial, end-to-end file. However, for the purpose of further processing and/or packaging, it is desirable to align the rod-shaped articles in a file of parallel rows.
This function has typically been performed by an apparatus which includes a conveyor for conveying a rod-shaped product or rod-shaped articles, a knife or other device for cutting the product into discrete rod-shaped articles if the product is not already separated into discrete rod-shaped articles at the maker, a rotary "spider mechanism" having a plurality of crank arms attached thereto, each crank arm having a holder for picking up an individual rod-shaped article from the serial end-to-end file and for moving the article to a position to be released to a rotary drum which forms the articles into a file of parallel rows. Such a transfer apparatus is well-known and conventional in the cigarette making art and is manufactured by, among others, Hauni-Werke Korber & Co. KG of Hamburg, Germany. Exemplary of such conventional transfer apparatus are the apparatus shown in U.S. Pat. Nos. 4,051,947; 4,408,621; and 4,465,083.
The spider mechanism is a complex device in that, in order to transfer rod-shaped articles from a moving end-to-end or serial file to a file of parallel rows, the pickup devices or article holders move parallel to and at essentially the same speed as the serial file to remove each individual article from the file in succession. Each holder is then rotated to a position where the lateral holder speed is essentially zero so that the article can be transferred to a rotary drum to convert the serial file along one axis to a file of parallel rows each parallel to the serial file axis. The holders are typically maintained essentially parallel to the serial file axis throughout their travel and follow an orbital or elliptical path in response to the combined rotation of the spider mechanism housing housing and the crank arms relative to the spider mechanism. The spider mechanism can also be operated in the reverse direction to convert a file of parallel rows to an end-to-end or serial file.
One typical spider mechanism is disclosed in the aforementioned U.S. Pat. No. 4,051,947 to Schumacher et al., the disclosure of which is hereby incorporated by reference. That patent illustrates a spider mechanism in which a plurality of holders and crank arms are rotatably mounted to a rotatable housing for counterrotation relative to the housing. In order to coordinate the relative motion of the housing, holders and crank arms, a planetary gear assembly is required. Because gearing is used, the gears must be lubricated and seals must be provided at the rotational interfaces between the holders and the crank arms and between the crank arms and the rotatable housing. The seals are prone to wear and ultimately to failure or leakage. Since there may be six to eight or more crank arm and holder combinations with as many as four seals for each combination, the number of individual seals subject to leakage can multiply rapidly. The consequence of such failure or leakage is that lubricant contaminates the rod-shaped articles being processed by the transfer device. This results in either costly sorting to eliminate the contaminated articles from the uncontaminated articles or, in the case of cigarette articles, disposal of the entire batch. In addition, the replacement of seals in the spider mechanism involves a time consuming disassembly and reassembly process.